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50 TECHNOLOGY MAY/JUN 2025 FDM ASIA | www.fdmasia.com

TRANSITION FROM and climate change concerns.

Consequently, many countries are promoting bio-based
FORMALDEHYDE- adhesives to reduce reliance on petroleum-based chemicals,

fossil fuels, and to improve indoor air quality for the alignment
BASED WOOD with the UN’s Sustainable Development Goals (SDGs).

Even if bio-based adhesives may currently be insufficient
ADHESIVES in obtaining the full adhesion performance of formaldehyde-

based adhesives, some research on alternative biomaterials
TO BIO-BASED such as soy protein, polysaccharides, lignin, and tannin has

shown promising results.
ALTERNATIVES Protein-based Adhesives

Protein-based adhesives are bio-based adhesives derived from
io-based wood adhesives are increasingly
receiving greater attention than those of animal or plant proteins, such as casein, collagen, gelatine,
synthetic formaldehyde-based adhesives from and soy protein.
petroleum sources in response to climate They offer several advantages such as biodegradability,
change. Bio-based adhesives offer low low toxicity, and strong bonding capabilities, particularly for
toxicity, lower greenhouse gas emissions, and porous materials such as wood and paper. They are commonly
increased sustainability with circular economy used for plywood and particleboard, as well as in textiles and
by promoting renewable and degradable food packaging.
sources, which generates a driving force for
the transition. By Saman Ghahri and Park In such applications, these adhesives can compete with
Byung-Dae, Kyungpook National University, synthetic options in the performance. However, challenges such
Yang Kong and Du Guanben, Southwest as shorter shelf life, performance variability due to different
Forestry University protein sources, and moisture sensitivity need to be addressed.
Ongoing research has focused on enhancing their properties
Formaldehyde-Based Wood Adhesives through formulation adjustments and cross-linking, positioning
Formaldehyde-based resins, such as phenol-formaldehyde (PF) protein-based adhesives as a sustainable alternative in various
resins, resorcinol-formaldehyde (RF) resins, phenol-resorcinol- applications and promoting their wider adoption.
formaldehyde (PRF) resins, urea-formaldehyde (UF) resins,

melamine-formaldehyde (MF) resins, and melamine-urea- Carbohydrate-based Adhesives
formaldehyde (MUF) resins, are widely used as adhesives for Carbohydrate-based adhesives are also bio-based adhesives
manufacturing glued laminated wood products, plywood, and derived from polysaccharides such as glucose, starch, chitosan,
wood-based composite panels. cellulose, and hemicellulose, which are commonly sourced
These adhesives have been used for almost 100 years, from plants.
owing to their low cost, good performance, and applicability These adhesives are valued for their biodegradability, low
to wood. However, these adhesives are posing health and toxicity, and renewable nature, making them environmentally

environmental risks, contributing to greenhouse gas emissions, friendly alternatives to synthetic adhesives.
and exhibiting slow biodegradation, which adds to pollution Carbohydrate-based adhesives exhibit good bonding